DESCRIZIONE
The present invention relates to a method for identifying a pepsin resistant alpha amylase enzyme for use in a feed supplement comprising: i) providing an alpha amylase enzyme; ii) admixing said alpha amylase with corn based feed and buffer solution comprising a pepsin concentration of 9000 U/ml at pH 3, 40° C., 500 rpm for at least 120 minutes and analysing alpha amylase activity on said alpha amylase compared to a control sample; wherein said control sample differs in that no pepsin is present during incubation; and iii) selecting an alpha amylase enzyme which substantially maintains alpha amylase activity under the assay conditions; feed supplements and feedstuffs comprising a pepsin resistant alpha amylase and the use of pepsin resistant alpha amylases in feed.